For the purposes of interpreting the disclosure made herein, the terms “CubeSat deployer”, “satellite deployer”, “satellite deployer system”, or derivations thereof are used interchangeably and should be considered synonymous. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Commercial development outside the earth's atmosphere, i.e., outer space, presents physical and logistics challenges and difficulties, hazards, and costs of a different nature from those within the earth's atmosphere. Because of these challenges and difficulties, satellites have been, and will continue to be the primary means for the clear majority of extra-planetary operations. Satellites have been used to explore space, gather and relay data, perform experiments, and do any other number of tasks.
Picosatellites, including CubeSats, provide a means for minimizing the financial barrier to space entry. The components used to build CubeSats are usually relatively inexpensive, off-the-shelf, electronics. The small size of these CubeSats and other picosatellites coupled with their uniform dimensions and inexpensive components make these satellites an attractive means of accessing space at a relatively small cost.
Miniaturized satellites can simplify problems commonly associated with mass production, although few satellites of any size, other than “communications constellations” (where dozens of satellites are used to cover the globe), have been mass-produced in practice. One reason for miniaturizing satellites is to reduce the cost associated with transporting them into space. Heavier satellites require more energy to transport them into orbit or open space, thereby requiring larger rockets with greater fuel requirements, which results in higher costs. In contrast, smaller and lighter satellites require less energy and less volume (requiring smaller and cheaper launch vehicles) and may be launched in multiples, or in other words, deployed in groups and at the same time. These small satellites, such as CubeSats and other picosatellites, can also be launched in a “piggyback” manner, using excess capacity available on already loaded launch vehicles.
The high cost of transporting mass from the surface of a stellar body into an orbit around a celestial body, or open space, has limited the development of aerospace activity. This high cost per unit mass has made minimizing the mass of the objects being sent into space particularly important. To achieve their purpose, CubeSats must be transported out of the atmosphere and released into space (whether that is into an orbit around a celestial body or into open space). Satellite deployers are used to store and protect satellites during their transportation into space. These satellite deployers protect the payloads stored inside of them from damage caused by the inherent stresses resulting from launching such payloads into space. The satellite deployer must also safely and efficiently deploy their satellite payloads into the correct trajectory once the system has reached space.
California Polytechnic State University (“Cal Poly”) initiated the CubeSat concept in 1999, to enable users to perform space science and exploration at lower costs. A basic CubeSat (“1 U”) is a 10 cm′ cube (one liter in volume) having a mass of not more than 1.33 kg. Other common sizes are available, including a “2U” that is 20 cm×10 cm×10 cm, and a “3U” that is 30 cm×10 cm×10 cm. Other sizes, such as a “6U” (30 cm×10 cm×20 cm), “12U” (30 cm×20 cm×20 cm), and “27U” (30 cm×30 cm×30 cm), have also been proposed, the dimensions cited herein are ‘nominal’. The standardized specification of CubeSats also allows for the deployment means of these satellites to be standardized as well. The standardization among both payloads and deployers enables quick exchanges of payloads without the need of customized payload-deployer interfaces. It also allows for easily interchanging parts across similarly dimensioned satellites.
Associated with the minimization of mass is the minimization of volume. This is important in the field of space transportation since there is a finite amount of usable storage volume inside of space vehicles. This minimization of mass and volume is important not only for satellites, but for the systems used to store, transport and deploy the satellites.
Satellite deployers may be designed as metal storage containers into which satellites are placed. These container-type satellite deployers usually provide a door at one end, through which payloads may be loaded and unloaded. After loading, the deployer system's door is sealed, and the deployer system is then mounted onto a launch vehicle which is responsible for transporting the deployer system, including any satellites or other space payloads stored therein, into space. Once the system is in space, the deployer may then be taken through an airlock so that the deployer is in contact with space. Once the deployer is in contact with space, the deployer's door is pointed in the desired direction
In a typical scenario, users build a CubeSat to perform a particular task in space, then coordinate with launch service providers to obtain “space-available” allocation on a delivery spacecraft, such as a launch vehicle, a shuttle, or a space station. Because the CubeSats are small, they may often be placed in the spaces between the larger payloads in the delivery spacecraft.
To deploy a CubeSat in space, a dispensing device is used to ‘push’ the CubeSat away from the delivery spacecraft. This dispensing device is also used to transport the CubeSat and to secure it to the delivery spacecraft. Current dispensing devices include the “P-Pod” (Poly's Pico-satellite Orbital Deployer), designed by Cal Poly, and the ISIPOD deployer, designed by ISIS (Innovative Solutions In Space). The P-Pod deployer accommodates a “3U” CubeSat, or, equivalently, three “1 U” CubeSats, or, one “1 U” CubeSat and one “2U” CubeSat”. The ISIPOD is also available in a variety of sizes.
It is well known in prior art that satellite deployers utilize various types of coiled springs to provide separation force between a deployer and a satellite being deployed. In particular, CubeSat satellite Poly-Pico Satellite (P-POD) deployer and other CubeSat deployers, such as the deployer in the applicant's patent application Ser. No. 14/445,271 dated Jul. 29, 2014. These springs are called deployment springs.
The P-POD and similar deployers are designed to carry standard format CubeSats which are stored in the deployer's rectangular outer aluminum box with an electrically activated spring-loaded door mechanism. After an electrical signal is sent from a launch vehicle, the spring loaded front door mechanism is opened and the CubeSat(s) are pushed out by a deployment spring exerting force on a pusher plate which pushes the back of the end CubeSat. The CubeSat(s) slide along guidance rails with the deployer spring force eventually ejecting the CubeSats(s) into orbit with a separation velocity of a few meters per second. The deployer spring utilized in these previous single-wide deployers are long coil springs and are constrained in the square cross section of the deployer's interior volume. When other variations of CubeSat geometry are desired (e.g. a double-wide CubeSat), the geometry of the constraining volume changes which permits the coil spring to buckle which reduces the applied force of the spring over the length of spring travel thus providing a varying and unpredictable deployment spring force to the satellite which is undesirable.
The disclosed subject matter helps to avoid these and other problems.